This is the five year renewal application for the Kansas Center for Mental Retardation and Human Development, one of the first Mental Retardation Research Centers funded by NICHD. Purpose. The Kansas MRDDRC has a continuing commitment to: 1) resolution of existing and newly evolving problems of mental retardation; 2) MR research of the highest quality and scientific merit; 3) facilitation of relevant multidisciplinary and interdisciplinary research and research training; and 4) translation of research findings into clinical application. Objective. The Kansas Center for Mental Retardation and Human Development is designed to accomplish the following specific objectives: 1) maintain a cohesive administrative system, particularly channels for planning, developing, managing, coordinating, disseminating and communicating research and research training activities in four thematic areas; 2) provide technical resources and common facilities to support and implement research and research training through its five scientific and technical cores; 3) design and develop research, research dissemination and research training programs relevant to critical problems of people with MRDD; and 4) develop intercenter collaborations, especially with other MRDDRCs. In order to guide the direction of our first objective, we have developed a central organizing theme. The Central Organizing Theme for the Kansas MRDDRC is the Integration of Mental Retardation Research at the Behavioral, Organ System, Cellular and Molecular Level. There are four thematic areas of research in support of this central integrating theme around which projects are focused. These research themes combine the work of 57 investigators on 63 projects served by an administrative core, and four scientific cores, including a technology enhancement core. Strengths of the KU MRDDRC are: strong behavioral and biological research, strong institutional focus and commitment; strong financial support from the University, the State and related centers; high level of federal research support; and excellent administration.